1. Technical Field
The invention relates to analyte particle manipulation. In particular, the invention relates to using surface plasmons to manipulate analyte particles.
2. Description of Related Art
The manipulation and analysis of extremely small analyte particles has attracted a great deal of attention in recent years. For example, spectral emission-based analysis methodologies such as, but not limited to, surface enhanced Raman spectroscopy (SERS) have been shown to have promise for analyzing single cells, bacterial spores, certain individual molecules, and similar nano-scale analyte particles.
However, the principal difficulty in performing such nano-scale analysis is often in collocating a target analyte particle and an analysis region so that analysis may occur. For example, SERS generally relies on collocation of the analyte molecules or particles and a region of high field intensity (i.e., a hot spot) on a SERS active substrate often referred to as a ‘hot spot’. Typically, collocation of an analyte particle with a SERS hot spot is an essentially random event. As such, in many cases the Raman active substrate is typically exposed to a large volume of media containing analyte particles in the hope that some analyte particles find their way to the SERS hot spot so that an enhanced Raman spectral response signal is generated. Unfortunately, a size of a hot spot on the Raman active substrate is generally extremely small which tends to adversely affect the probability of capture and subsequent analysis. A similar issue of analyte particle and active region exists in many other analytical techniques.
Attempts to address the collocation problem and further, in the interest of simply being able to work with nano-scale analyte particles on an individual basis, various nano-manipulation techniques have been developed. For example, optical tweezer that employ an optical field gradient to trap and hold analyte particles have been demonstrated. The optical tweezer enables an analyte particle to be selected, captured and held by an optical field of the tweezer. Once held by the optical tweezer, the analyte particle may be delivered to a SERS hot spot, for example, by essentially moving the optical field of the optical tweezer (often by a mechanical means) to a location of the hot spot. However, providing precise movement of the optical field and knowing where to place a captured analyte particle (e.g., where the hot spot is located) often represent significant obstacles to the use of optical tweezers.
As such, means for capturing and controllably manipulating analyte particles is of great interest both to the field of analysis and in a general area of nano-manipulation. Providing such means would satisfy a long felt need.